Flavourings || Blended Flavourings

4 Blended FlavouringsWilli Grab

Flavourings: Production, Composition, Applications, Regulations. Second Edition. Edited by Herta ZieglerCopyright © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 978-3-527-31406-5

Antioxidants and Preservatives 393

394 Blended Flavourings

Flavour Profiles 395

4.1 Introduction

It is simple to concentrate fruit juices to a fully flavoured concentrate. It is easy tomake a concentrated extract of spices with an organic solvent. It is possible to distiloff the flavour of apples into a 150 fold concentrated product or to develop a meatflavour by reacting reducing sugars with amino acids. But it is very difficult and veryexpensive to prepare from strawberries a highly concentrated strawberry flavour withthe taste of freshly picked strawberries, which is stable in a baking process forbiscuits. The prepared flavouring raw materials discussed in chapter 3 (essential oils,extracts, juice concentrates, process flavourings, biotechnological engineered flavour-ing products) represent more or less the whole flavour profile. In contrast to them,compounded or blended flavouring products get their final flavour profile only by thewell balanced mixture of individual flavouring components, including the abovementioned materials.

The merit of blended flavourings is adaptability and flexibility to adjust the parame-ters of a flavour to the desired purpose:

flavour profile, solubility, cost, stability, viscosity, colour, density, legislative aspects,health aspects, technological behaviour, heat stability, enzymatic resistance, interac-tions with food ingredients, various delivery and releasing systems.

The progress of research in understanding flavour development, biosynthesis, compo-sition, perception and technological behaviour allows the flavour industry today topropose an adequate flavouring for almost all requests.

4.1.1 Flavour Analysis

The progress in trace analysis (high resolution capillary gas chromatography com-bined with mass spectrometry, high resolution nuclear magnetic resonance spectros-copy, high performance liquid/liquid chromatography, head space analysis, chiral andisotopic analysis) revealed an enormous mass of information on the formation, com-position and interactions of natural flavours. Today we start to understand why andhow food smells and tastes, although many questions are not yet answered.

4.1.2 Flavour Profiles

The general basic flavours of food can be divided into fruity, meaty, vegetable, spicyand roasted notes. The comparison of the composition of food shows a direct correla-tion between its composition of tasting materials and the basic tastes (see Table 4.1).

The comparison of the composition of the main, tasting ingredients in food shows thefollowing correlation:

– Fruity notes are related with a balanced sugar/acid ratio, without salt andnucleotides. Some fruits contain bitter or astringent notes.

– Mushroom notes are combined with nucleotides.– Vegetable notes are based on a balance of sugar, acids and salt.– Nut notes are mainly based on bitter and astringent notes.– Meaty notes are based on a balance of salt and nucleotides.


Table 4.1: Tasting materials and basic tastes

(percentage in dry, edible matter)

The only way to describe and measure “flavour” is to use descriptor words in analogyto “known standards”. The precision of a flavour profile description strongly dependson the clear definition of the standards:

– The descriptor “floral” can mean anything of rose, jasmine, hyacinth, laven-der, orange flower, lily of the valley smell.

– The descriptor “floral, rosy” is more precise as it describes the floral note ofa rose. But it is quite obvious, that many different roses with different odoursexist: heavy, sultry perfumy, fresh fruity, even minty and lemon notes.

– The descriptor “floral, rosy, rose oil” is rather precise because the recogni-tion of the odour of rose oil can be trained in a panel. But as there existvarious qualities of rose oil even a more precise description is sometimesnecessary.

– Only the descriptor “floral, rosy, phenyl ethyl alcohol” identifies a clear,reproducible standard, as phenyl ethyl alcohol is available in any quantitiesall over the world in a standard quality.

The merit of such a precise description is that its odour is easy to reproduce and it canbe shown and explained to other people. The drawback is that no common flavour isjust as simple as a pure chemical.

sugar salt acids nucleotides bitter astringent

Strawberry 50.48 0.05 9.52 0.01 0.01 0.01

Apple 2.79 0.03 4.08 0.01 0.03 0.07

Orange 55.94 0.01 8.39 0.01 0.07 0.03

Mushroom 5.91 0.17 1.08 1.08 0.02 0.01

Salad 21.40 0.60 0.20 0.04 2.00 0.02

Broccoli 24.27 0.39 2.91 0.10 0.49 0.10

Carrot 38.98 1.53 2.54 0.08 0.08 0.04

Hazelnut 1.05 0.01 0.01 0.00 0.11 0.11

Walnut 1.05 0.01 0.01 0.00 0.52 1.05

Veal 0.00 0.64 0.13 0.86 0.00 0.00

Beef 0.00 0.72 0.11 0.76 0.01 0.01

Chicken 0.00 0.59 0.11 0.73 0.01 0.01

Salmon 0.00 0.29 0.09 0.87 0.00 0.00

Flavouring Raw Materials 397

Furthermore unexpected interactions may disturb the perception, for example: 3-methyl cyclopent-2-en-2-ol-one (corylon) has a burnt, roasted, maple and coffee likecharacter.

Allyl hexanoate has a sweet, fruity, candy, pineapple like character.

The combination of 9 parts corylon and 1 part allyl hexanoate is recognized by themajority of people as spicy, celery like.

A professional description of flavours uses as precise descriptors as possible. Chemi-cal analytical results are combined with sensory analysis of the identified componentsto assess the relative importance and contribution to the flavour profile. Key ingredi-ents or character impact compounds (CIC) are important components “sine qua non”to impart the typical, product characteristic, flavour, e.g. anethol for anise, eugenol forclove, 3-methyl butyl acetate for banana or ethyl butyrate to improve the juiciness oforange juice.

4.1.3 Flavouring Raw Materials

The characterization and description of raw materials is reversed to the description offood flavours and it depends strongly on the individual’s experience, expertise, train-ing and vocabulary. The flavouring raw materials are best described in view of theirpotential use and in analogy to peculiarities of known products of natural or commer-cial origin.

A complete description of a flavouring raw material has to include:

– Odour: from the product; on a blotter, fresh, and throughout the dry-out;intensity character.

– Taste: in water, with/without sugar, salt, dosage range, change of character atdifferent concentration levels.

– Natural occurrence: analytical results from literature or through own re-search and a critical evaluation of its importance.

– Potential use and application: this is the basic source of creativity for theflavourist.

– Sensory values: evaluate the olfactive purity through careful trace analysisusing sniffing techniques. Determine threshold value, odour value, anosmia.

– Physico-chemical parameters: solubility, vapour pressure, density.– Chemical parameters: chemical structure; reactivity towards functional

groups and food ingredients; stability in low pH, heat, enzymatic activity,oxygen, light.

– Legal aspects: natural, nature-identical, artificial, GRAS, kosher status, halal,local or company specific limitations.

– Cost: put the price into relation to the flavouring cost (= price/dosage). Thusa very expensive material may cause low flavouring costs due to a lowdosage level in the finished product.


Example Benzaldehyde (nature-identical)

Odour of the product: strong, persistent, bitter almond, chemical pungent.

Odour on the blotter: bitter almond, sweet, black cherries, evaporates within 24 hours

Taste in water: at 0,2-20 ppm: bitter almond, cherry, dry

Occurrence in food: mainly fruits, bitter almond, apricot, peach, cherry, cinnamon,plum, black tea

Potential use: bitter almond, cherry, grape, red wine, apple pip, apricot kernel, peachkernel, plum, vanilla, pistachio

Olfactive purity: 95% benzaldehyde, 4,5% benzoic acid, 0,3% benzyl alcohol, tracesof benzoin (1-hydroxy-2-oxo-1,2-diphenyl ethane), benzyl chloride

Threshold value: beer: 1,5-3 ppm, wine: 2-3 ppm, 75 ng/l in air

Odour value: 81200

Dosage range (in water): 0.05-30 ppm

Solubility in water: 6580 ppm

Solubility in organic solvents: good

Formula: C6H5CHO, molecular weight: 106

Reactivity: is easily oxidized to benzoic acid through air oxidation. Reacts withalcohols to form acetals (e.g.: ethanol, 1,2-propanediol); may form Schiff Bases withamines

Legal aspects: nature-identical, GRAS, kosher

4.1.4 Flavouring Composition

Fig. 4.1: The Flavour Creation as a Theorem of Addition

Flavouring Composition 399

Fig. 4.2: a Flavour profiles. b Flavour profile, calculated.

The flavour profile of a composition can be “calculated” or described as a linearcombination of the vectors of the individual components using the “flavour quality”as the direction of the vector and the intensity as its length. Components with a similarquality harmonize well and strengthen each other. Components with different qualityadd a new dimension to the flavouring: a trace of lemon oil in a vanilla flavouringturns it into a fresh cake flavouring.

At an “equal contribution” all ingredients have about the same intensity and thereforethe resulting flavour profile is “rounded off” with no dominating component.

Flavourists are trained to detect and describe hundreds of different odours and tastes.They do this in a dynamic way: sniffing a product at intervals shows many aspects ofthe flavour profile due to changes in the perceived proportions. This is very obviouswhen sniffing a concentrated flavour on a paper blotter or during food eating and


degustation sessions: tea and coffee tasters use a very noisy way to evaporate andseparate the flavour in their palate to distinguish minor differences.

David Laing has shown that nobody is able to distinguish more than 3-5 molecules ina single sniff. This can be explained by the detection limits in triangle tests: relativeconcentration differences below 20% in a mixture are very difficult to differentiate.

Fig. 4.3: Sniffing detection limits in compositions

From this we may conclude that any flavour impression can be generated by only afew character impact molecules. My experience confirms this to a good degree: theselection of the molecules is very critical. However, in order to create a commercialflavour, the flavourist has to mix more than just these few molecules:

– A flavour must be “robust” in the food. A combination of molecules withsimilar profiles compensates small changes and losses.

– To protect intellectual property, the flavourist will try to “hide” the keymolecules.

– A more complex flavour fits to more individual palates and preferences.

Some key impact molecules are very unstable, expensive or just not available on theshelf. They have to be replaced and mimicked by more stable, common raw materials.

A standard compounded flavouring can be divided into various parts:

– the key base contains all the important characterizing trace components.– general basic materials: esters for fruits, pyrazines for roasted products.– rounding-off products: vanillin, maltol, 2,5-dimethyl-4-hydroxy-furan-

3(2H)-one.– sweet background, body: 2-methyl-5-ethyl-4-hydroxy-furan-3(2H)-one.

The flavouring concentrate represents the complete flavour profile in the most con-centrated form and it also includes general rounding-off materials to impart a basicbody for sweet taste (e.g. vanillin, maltol, 2,5-dimethyl-4-hydroxy-furan-3(2H)-one).

The flavouring is diluted with a carrier. This carrier fulfils several purposes:

Flavouring Composition 401

– it adjusts the technological properties of the flavouring to the need of theusers.

– as a diluent it reduces the concentration of the flavouring to a practical, easyto be applied level.

– it reduces the risk of spillages.– it stabilizes the flavouring.– it dissolves all flavouring components into a homogenous product.

The basic task in the creation of flavourings is to:

– mix the right components– in the right proportions.

The example below illustrates this task: a selection of 16 components mixed in theright proportions results in 4 different flavours. The key components (CIC) in thisexample are:

Apple: Hexanal, (E)-2-HexenalBanana: Isoamyl acetate, Eugenol, VanillinPear: Heptyl acetate, Citronellyl acetatePineapple: Allyl caproate.

Table 4.2: Simple flavour combinations

Apple Banana Pear Pineapple

1-Butanol 30 5 30 1

2-Methyl butanol 50 5 50 5

1-Hexanol 30 5 40 1

Amyl acetate 50 10 20 5

Isoamyl acetate 5 150 5 5

Ethyl butyrate 5 40 10 10

Amyl butyrate 5 30 20 20

Heptyl acetate 5 5 100 5

Ethyl-2-methyl butyrate 5 10 5 20

Allyl caproate 5 5 5 120

Citronellyl acetate 5 5 40 1

Hexanal 100 1 5 1

(E)-2-Hexenal 100 10 30 5

Benzaldehyde 0.1 0.2 0.2 0.1

Vanillin 1 30 1 30

Eugenol 0.1 2 0.2 0.1

Ethanol 693.8 686.8 638.6 770.8

1000 1000 1000 1000


4.1.5 Flavour Release

The profile of an aroma depends on the release of the flavouring molecules duringeating or drinking: only molecules that reach the receptors in the nose are perceivedas aromatic if the concentration at that moment is above the threshold. From this wemay conclude that the composition of a food strongly influences the flavour profile.A given flavour composition, applied in a beverage or in a fatty ice cream, will delivera different flavour impression: lipophilic components like long-chain fatty aldehydesare dissolved in the fat phase of the ice cream and their vapour pressure above theproduct is lowered, thus reducing their flavouring impact. In the beverage, they are ina hydrophilic environment, not soluble in water and therefore “pushed” out of theproduct into the headspace: the higher concentration leads to a high impact of thealdehydes.

Fig. 4.4: Aroma release and perception

Example: A balanced vanilla composition with lemon oil gives a nice, fresh vanillaice cream. The same flavour applied in carbonated water has a sweet lemon character.

Extensive research in the past 20 years has elucidated the physical and mathematicalbackground of this phenomenon. The main factors influencing the flavour release arethe partition coefficients between the aroma molecules and the various phases in food(fat, water, emulsion, solid, air) and the mass transport between the phases. Thechanges of the food matrix during eating (chewing, salivation, swallowing) furtherinfluence the individual perception of a flavour. Reversible and irreversible reactionsbetween the flavouring molecules and the food ingredients modify the flavour release:proteins are strong “binders” of carbonyl and sulphur components, starch and pectin“encapsulate” the molecules.

Example: Flavouring soy milk is extremely difficult, as many important flavourimpact molecules are irreversibly bound to the soy protein.

Another effect of “unwanted flavour release” is the loss of flavourings during foodprocessing (baking, extrusion) and storage.

Example: Baking a dough results in an almost complete loss of volatile molecules: thebaking process acts like an efficient “water vapour distillation”. As a result, thebakery smells fantastic; the product is dull.

Flavour Release 403

The flavour industry has to compensate these effects and balance the flavour in sucha way that its expected flavour profile develops after processing, storage and duringconsumption of the food. The flavourists have different ways to achieve this goal:

Trial and error combined with application trials and stability tests. The flavourindustry has a vast experience concerning the performance of their flavourings and“guessing” is in many cases the best approach for a new flavour composition in aknown food application.

Mathematical model calculations using verified models and well documented data-bases. Although these models are very complex, it was possible to develop computerprograms and fill databases with a reasonable effort. This program, linked into thedaily creation process of the flavourist allows a prediction of the adjustment of acomposition for different food applications.

Table 4.3: Flavour reformulation by computer

Encapsulation. The flavour industry is using different ways to protect flavouringsfrom losses during storage and processing and to adjust the release in a desiredmanner. A pure mixture of a liquid flavour with a carrier like starch results in a dry,but still very sensitive adsorbate. Volatile parts are lost and terpenes will be oxidized.Spray drying is often used to transform liquid flavourings into dry powders. Spraydrying in combination with coating in double stage dryers gives an additional protec-tion against oxidation. Spray dried powder flavours are extensively used in the foodindustry. They are easy to handle, relatively stable and possess good solubility inwater. Extrusion of a flavour-sugar syrup emulsion, combined with instant chillingand solvent washing gives rather stable products, mainly for the oxygen sensitivecitrus range; special treatment is required for tropical environment. The selection ofthe carrier matrix (mainly gum arabic, maltodextrin and modified starches) is criticalfor the stability of the end product. Another concept is the encapsulation in a proteinor gelatine matrix: these products are not water soluble and quite heat stable. Theflavour release depends on mechanical force or higher temperature, an ideal behav-iour for heated food products (e.g. baked biscuits), shown in Table 4.5.

Original Application: Drink Yogurt (3.5% dat)

New Application: Soft Drink (0% Fat)

Concentration for same Perception

Soft Drink

Yogurt Sniff Mouth

cis-3-Hexenol 60 48 48

Hexylacetate 220 38 50

Linalylacetate 370 11 50

-Undecalactone 350 11 50

Total: 1000 108 198

Low fat products have relatively strong smell compared to taste!


Table 4.4: Carrier Systems

Table 4.5: Controlled release systems

4.1.6 Application of Flavourings

Flavourings as such are not intended for direct consumption. Only their appropriateinclusion into food systems reveals their value to impart taste and quality. Experiencehas shown, that flavourings are strongly influenced by the nature of the food matrix,by food processing and through storage conditions:

AdsorbatesFlavour composition is adsobed into porous (car-bohydrate) matrix.

• Dry product• No or limited protection of flavour com-

pounds

SpraydriesFlavour emulsion is dried in spraying tower.

• Dry, free-flowing product• Good oxidative stability of encapsulated fla-

vour• Sensitive to humidity• Small particles

GranulatesFlavour emulsion sprayed on nucleus; agglomera-tion in fluid bed dryer; optionally caoting of parti-cles.

• Dry, free-flowing product• Good oxidative stability of encapsulated

flavour• Intermediate particle size• Limited controlled release properties

(coatings)

Melt extrudatesFlavour composition is mixed with hot carbohy-drate melt, extruded into cold solvent.

• Dry, free-flowing product• Excellent oxidative stability of encapsu-

lated flavour• Moderately sensitive to humidity• Large particles

Fat encapsulationFlavour composition adsobed by liquid of solid tat; tat dispersed or solidified into small particles

• No significant protection of encapsulated flavour

• Particles sensitive to mechanical forces and temperature

• Flexible particle size• Limited controlled release properties

ExtrudatesFlavour composition encapsulated in high-molecu-lar weight matrix by extrusion process

• Good oxidative stability of encapsulated flavour

• Stable particles• (Very) large particle size• Tunable release profiles

Polymer capsules:• Core-shellFlavour composition entrapped in capsule consist-ing of solvent core covered by protein shell

• Dry product or liquid dispersion• Limited (oxidative) stability of encapsu-

lated flavour• Flavour can be loaded in ‚empty‘ particles• Flexible particle size• Relatively slow release/burst-like release

• MatrixPolymer matrix with dispersed oil or flavour drop-lets

• Dry product• Limited (oxidative) stability of encapsu-

lated flavour• Flavour can be loaded in ‚empty‘ particles• Tunable release

Flavouring Production 405

– heat evaporates the volatile components, induces Maillard reactions.– fat absorbs liposoluble flavourings, thus reducing their flavour impact.– proteins react with aldehydes.– low pH hydrolyses esters, catalyzes chemical reactions.– oxygen oxidizes lipids, terpenes etc.

Compounded flavourings are well suited to be adapted to the needs of the users:

– an “unbalanced” flavouring reveals a balanced profile in the processed fin-ished food.

– the replacement of unstable aldehydes by equivalent alcohols results in fla-vourings with improved stability.

– heat stable butter flavourings contain more lactones, less diacetyl.– precursor systems constantly deliver volatile flavouring molecules.– encapsulated flavourings are protected against heat, oxygen, acids or en-

zymes.– flavour profiles can be adapted to maximum consumer preference.– original, fantasy and true to nature flavour profiles can be created.

It is important to consider the fact that the dosage of a flavouring in finished foodstrongly influences its profile: a low dosage just adds some slightly modifying bodynotes; a regular dosage imparts the characteristic profile: a high dosage may add somechemical off notes. A careful selection of the flavouring as well as an appropriatelyadjusted dosage are essential for the success of flavoured food products.

4.1.7 Flavouring Production

Compounding flavourings on a production scale is in principle simple: just mix theright components in the right proportion. However modern flavouring factories arehigh tech operations to handle the customer requests in an efficient manner. Hundredsof flavourings are specifically customer made and therefore deliveries are oftenprepared against customer request only. Approximately 2000 different raw materialsof various consistencies (liquid, viscous, solid, crystalline, powder) are used. They arestored under controlled conditions (cold, ambient, warm). They have varying inherentcharacteristics: they can be sensitive, reactive, volatile, strong smelling, noxious.They are used from very small quantities up to large volumes, stored in tanks. Qualitycontrol has to control measurable and non measurable properties like density, refrac-tive index, component concentrations, odour, taste. Flavouring mixtures contain froma few up to dozens of components. They range from parts per million up to 99%. Theproduced quantities range from 100 g up to several tons batches. Therefore, modernflavouring factories are highly sophisticated: laser scanners are used to identify prod-ucts and batch numbers, mixing robots automatically mix small to medium quantities.Dispense lines and dispense clusters, supplemented from tank farms mix medium tolarge quantities of flavourings, all computer controlled. Nevertheless, people are stillworking in this high-tech, strong smelling environment: there exist no economiccomputers nor robots for all critical exceptions: mixing small quantities, solid mate-rial, viscous material, badly miscible or soluble components into a large number ofproducts still needs the skill of trained people (see Fig. 4.5-4.12).


Fig. 4.5: Automatic, computer controlled compounding

Fig. 4.6: Automatic dosing of flavouring components, mixing tanks for balance

Flavouring Production 407

Fig. 4.7: Automatic compounding, handling equipment for mixing tanks

Fig. 4.8: Raw material storage for automated liquid compounding


Fig. 4.9: Robotic for automated compounding of small batches

Fig. 4.10: Cluster of dosing valves for liquid compounding

Flavouring Stability 409

Fig. 4.11: Manual compounding of small quantities

Fig. 4.12: Flavourist at work

4.1.8 Flavouring Stability

Dealing with flavourings, quality changes in finished products and instability prob-lems with flavourings are often encountered. From our experience we know, that100% stability is not attainable:

– the intensity is gradually reduced.– the quality and flavour profile changes before and after application and

during the shelf life of the final product.

Whenever we want to understand flavouring stability, we have to know somethingabout:

– the composition of flavourings– the raw materials


– the characterisation of the flavouring– how to estimate flavour changes– the factors responsible for flavour changes– how to prevent flavour changes.

Traditional flavouring raw materials are produced under rather “harsh” conditions:heat, distillation at high temperatures, concentration, extraction. These result in thedestruction of all sensitive substances. Modern flavouring raw materials are producedunder controlled and careful conditions: low pressure, low temperature distillation,extraction with low boiling solvents or CO2, careful selection of fresh, high qualityraw materials. Therefore sensitive substances survive the production process andinfluence the quality with all positive (flavour profile) and negative effects (stability).

For an objective description of a flavour we have to identify, evaluate and quantifythe sensory properties of the components. The flavour characteristic describes thesensorial behaviour of individual components dependent on the concentration, thethreshold value and its odour value.

An objective stability test has to determine whether

– important components disappeared or– undesirable components with a high odour value developed.

Discussing flavouring stability, we have to distinguish between:

– the stability of the flavouring itself– its stability in food– flavour changes during processing– flavour changes during the storage period.

We distinguish:

physical stability:

– evaporation of volatile components– crystallisation of non soluble material (mainly in liquid flavourings)– phase separation (in emulsions and washes)– solubility (in fat-containing food)– ab- and adsorption effects in complex food systems;

chemical stability:

– reactions with food components– reactions of flavouring components through degradation, rearrangement, ox-

idation;

sensory stability:

– what is the standard sample to compare with (how is it stored?)– what does the customer expect and remember– how does the customer evaluate the samples.

Fruit Flavours 411

The most important factors influencing flavourings are:

– heat treatment (evaporation of volatiles, formation of new flavouring compo-nents)

– oxidation (of terpenes, lipids)– enzyme activity (degradation and formation of flavouring components)– low pH (acid catalysed reactions)– fat absorption of liposoluble components– protein reactions and inclusions.

4.2 Fruit Flavours

The flavours of fruits are generally characterized by expressions like:

juicy: high, free water content with balanced, fruit-characteristic,sugar/acid ratio representing the juicy, sweet, sour taste.

fresh: refreshing impression, supported by the acidity and low mo-lecular weight flavouring substances such as acetaldehyde,methyl butyrate, and some green notes like (E)-3-hexenol.

fruity: a general fruity-estery impression of low molecular weightesters like ethyl acetate, ethyl butyrate, butyl acetate, 3-methylbutyl acetate, methyl caproate or ethyl caproate.

green: the fresh, unripe impression of immature fruits represented by(E)-2-hexenal, (E)-2-hexenol, (E)-2-hexenyl acetate, hexanal,often combined with high acidity and low sugar content.

ripe fruity: during the maturation process, the flavour reaches its optimumconcentration and balance, often combined with a high sugar/low acid ratio. Ethyl-3-methyl butyrate, 3-methylbutyl bu-tyrate, ethyl caproate, ethyl-3-methyl but-2-enoate, methylcinnamate are typical examples of this general impression.The ripe, fruity character of fruits is supported by traces of thefruity, caramelic notes of 2,5-dimethyl-4-hydroxy-furan-3(2H)-one, 2,5-dimethyl-4-methoxy furan-3(2H)-one andmaltol.

sweet, creamy: a soft sweet impression of vanillin or maltol.

floral: often understood as a non-characteristic general odour note offlowers, even with a slight perfumistic background. Traces ofalpha-ionone, beta-ionone, damascenone, geraniol or phenylethyl alcohol may be responsible for this character.

floral, fruity, sweet: a general note of flowers with a spicy, food-appealing back-ground represented by linalool, alpha-terpineol

spicy: a general impression of traditional spices like clove, cinna-mon, eugenol, cinnamicaldehyde, 3-phenyl propyl acetate,


ethyl cinnamate. But “spicy” is also used in connection withsavoury, HVP-like, lovage-like impressions.

pip, stone note: the astringent, nutty, woody almond note of the broken seedsmay be represented by the bitter almond note of benzalde-hyde, the woody character of damascone or the green, nuttynote of trimethyl pyrazine.

overripe, fermented: the impression of overripe fruits in the first phase of degrada-tion and fermentation. The balance of the flavour is distorted,high concentrations of ethyl esters, mainly ethyl butyrate,ethyl caproate, ethyl octanoate, ethyl decanoate are combinedwith traces of sulphur components like methyl mercaptane,methyl thioacetate, methyl thiobutyrate.

canned, preserved: the canned, preserved note develops during the sterilizationprocess and the following storage time. The most importanteffects are the loss of the fresh, fruity, typical aldehydic andestery notes and the formation of Maillard reaction productslike 5-hydroxy methyl furfural. The sulphur components hy-drogen sulphide, methyl mercaptane support the fusty charac-ter. A metallic off-taste is often produced by the lipid degrada-tion product (Z)-1,5-octadien-3-one.

cooked: during cooking of fruits, most of the volatile esters, aldehydes,alcohols and hydrocarbons are lost by a water vapour distilla-tion, thus losing all the fresh fruity character. The basiccooked note is supported by the acid catalyzed formation ofcaramel like Maillard reaction products from fruit sugars: car-amel notes of 2,5-dimethyl-4-hydroxy-furan-3(2H)-one, 2,5-dimethyl-4-methoxy-furan-3(2H)-one, 5-hydroxy-methyl-fur-fural, 3-hydroxy-2-methyl-4-pyrone.

Character Impact Compounds (CIC):

All fruit flavourings are fruit-typically characterized by some key ingredients todistinguish them from each other (see the detailed description of the individual fruits).

4.2.1 The Flavour of Natural Fruits

Fruits are the main player in the world of flavours: A vast number of fruits grow innature and are planted throughout the world. They are consumed not only for theirnutritional and health value, but mainly for their highly esteemed flavour and taste.More and more fruits are commercialized worldwide from all continents. Peopleexperience new tastes and flavours when travelling abroad. Thus processed fruits areused in many industrial food products as main ingredient or as flavour modifier.

World of Commercially Important Fruit Flavours 413

4.2.2 World of Commercially Important Fruit Flavours

Table 4.6: World production of fruits

Almond (Prunus amygdalus, Rosaceae) (G: Mandel, F: amande)

The commercial almond is the pit of the peach-like fruit, not consumed as such. Theraw almond has a nutty, fatty, slightly green and benzaldehyde character. Almondsare generally roasted to get the typical roasted, nutty, popcorn, slight caramel charac-ter with a very low benzaldehyde note. The well known bitter almond oil is isolatedfrom fresh raw bitter almonds and consists mainly of pure benzaldehyde.

CIC: Non-enzymatic-browning compounds: 2,5- and 2,6-dimethyl pyrazines, trime-thyl pyrazine impart the fresh, green, nutty character, 2-methyl-6,7-dihydro-5H-cy-clo-penta-pyrazine is responsible for the roasted-nutty note and 2,5-dimethyl-4-hy-droxy-furan-3(2H)-one supports the caramel like, sweet overall impression.

Most commercial almond flavourings contain a high amount of benzaldehyde, whichrepresents more the fresh bitteralmond type.

Apple (Malus sylvestris var. domestica, Rosaceae)(G: Apfel, F: pomme, S: manzana, I:pomo, mela)

Due to its high commercial value the flavour of apples belongs to the best known anddocumented natural flavours. Many hundreds of varieties have been bred and areproduced throughout the world. Therefore, each person has its preferred and “typical”apple flavour: a juicy, refreshing, sweet-acid, watery taste is combined with fruity,estery, green notes, supported by species characterizing sweet, floral impressions.

CIC: (E)-2-hexenal, (E)-2-hexenol, (E)-2-hexenyl acetate and hexanal are responsiblefor the fresh, green-fruity basic flavour. Ethyl-2-methyl butyrate, hexyl acetate sup-port the fruity-estery note and additional compounds like 3-methyl butyl acetate,hexyl-2-methyl butyrate, damascenone, linalool impart the specific species character.Benzaldehyde intensifies the pip note.

Fruits 360 [in mio tons]

GrapesOrangesBananasApplesPineapplesPeachesPearsMandarins, tangerinesLemonsPlumsCoffeeGrapefruitsCocoa

605548401099876652


Apricot (Prunus armeniaca, Rosaceae)(G: Aprikose, Marille, F: abricot, S: albaricoque)

The taste of apricots is sour-sweet with a fresh, fruity, perfumy, sweet, creamy odour.Dried apricots have lost some of the fruity, perfumy odour and are rather sour.

CIC: Linalool, phenyl ethanol and traces of damascenone impart the floral, perfumynote, 4-decanolide adds the sweet, heavy lactone character and (E)-2-hexenal, (E)-2-hexenyl acetate impart the fruity, fresh, green topnote.

Banana (Musa sapientum, M.paradisiaca, M. acuminata, M. balbisiana and hybrids thereof, Musaceae)

(G: Banane, F: banane, S: platano)

Bananas are the most important single fruit for direct consumption. Over 200 typesare produced with different tastes and uses. We can distinguish 2 main uses: directconsumption of ripe, fruity, sweet species and cooking varieties of the more bland,mealy, slightly astringent bananas rich in starch. Bananas have to be artificiallyripened near the consumer as ripe bananas are not stable for transportation. Theflavour develops from a bland, slightly sour, astringent character over a fruity, fresh,sweet typical estery ripe banana note dominated by 3-methyl butyl acetate to anoverripe sweet, creamy, spicy, full-flavoured estery character.

CIC: 3-methyl butyl acetate represents the fresh, estery, fruity-sweet character remi-niscent of technical solvents. Eugenol is responsible for the spicy part of ripe andoverripe bananas. A series of volatile esters (3-methyl butyl butyrate, 3-methyl butyl-3-methyl butyrate, 4-hepten-2-yl acetate) round off the general fruity note and vanil-lin adds the sweet, creamy part.

Black Currant (Ribes nigrum, Saxifragaceae)(G: Schwarze Johannisbeere, F: Cassis, S: Groselheira negra)

Black currants are of interest mainly in France and the United Kingdom due to theirstrong, special flavour: a sour, fruity taste with a catty, sulphurous fresh odour.

CIC: Ethyl butyrate contribute to the fruity, estery note; linalool, alpha-terpineol,citronellol and damascenone support the floral, fruity ripe character and 1,8-cineolimparts the freshness. 4-methoxy-2-methyl-2-mercapto butane is responsible for typ-ical catty sulphurous black currant note. Extracts of the black currant buds are moregreen, herbaceous but they also contain the sulphurous CIC. A similar note, 8-mercapto-p-menthan-3-one has been identified in buchu oil and is often used toimitate the catty black currant aspect.

Cherry (Prunus avivum, sweet cherry and Prunus cerasus, sour cherry, Rosaceae)(G: Kirsche, Morellen, F: cerises, S: cereza, guinda, I: ciliega)

The basic varieties, sweet and sour cherry, have been crossed to over 600 types. Thetaste of the stone fruits is acid, sweet and slightly astringent. The balance depends onthe ripeness and especially on the species. The flavour is fresh, fruity, green, floraland slightly spicy and develops a strong bitter almond, benzaldehyde character whencrushed.


CIC: (E)-2-hexenal, hexanal, (Z)-3-hexenol are responsible for the fresh, green im-pact, (E,Z)-2,6-nonadienal and phenyl acetaldehyde add a full heavy green, fattycharacter. Linalool, geraniol and damascenone bring along the floral aspect, 3-methylbutyric acid the fruity and eugenol the spicy note. Tannic acids are responsible for theastringent mouthfeel. The very typical black cherry note, benzaldehyde, is overdosedin most cherry flavourings. The art to create a good cherry flavouring is to use thehighest possible dosage of benzaldehyde and surround it with other flavouring mate-rials to get the least effect of benzaldehyde.

Citrus Fruits (see also chapter 3.2.2.2)(G: Agrumen, F: hesperidees)

Citrus fruits are among the most important fruit crops. Due to the high cross breedingactivities of agricultural biologists, a clear identification back to the original speciesis very difficult or almost impossible.

Their flavour is the most popular flavour in beverages. It is well appreciated due to itsrefreshing, sour, sweet taste and its refreshing clean flavour. The low cost of the rawmaterial and its high flavour value are other important success factors. The citrus peelis rich in essential oils, which are recovered mainly for flavouring purposes.

(1) Orange (Citrus sinensis, Rutaceae), see Tab. 3.22 for composition(G: Orange, Apfelsine, F: orange, S: naranja, I: arancia)

The taste of orange juice is refreshing, sour, sweet with a fruity, juicy flavour. Sometypes of oranges may develop a lasting bitterness. It is often overpowered by acontamination by the peel oil. This oil has a strong terpeny, aldehydic, non fruity orjuicy character. The taste of blood oranges is more tart with a slight berry, floral note.

CIC: Acetaldehyde, although weak in smell and taste, is an important contributor tojuiciness and freshness. Ethyl butyrate and (E)-2-hexenol add the fruity, green noteand alpha-pinene, octanal and decanal are responsible for the green peely, aldehydicorange note.

(2) Lemon (Citrus limon, Rutaceae), see Tab. 3.18 for composition(G: Zitrone, F: citron, S: limon, I:limone)

We have to distinguish essentially between two different parts: – the lemon juice andthe lemon peel. The juice has a very strong acidic taste from the high citric acidcontent (50 g/l) with a refreshing juicy aroma, far away from the peel oil.

CIC: The weak juicy flavour is based on geraniol, geranyl acetate and neryl acetate incombination with linalyl ethyl ether and myrcenyl ethyl ether. The cold pressed peeloil has a high terpene content. Its flavour is dominated by citral, gamma-terpinene andalpha-pinene. Citral is recognized as a very important contributor to the fresh lemoncharacter, although it decomposes within a few weeks in acidic soft drinks.


(3) Lime (Citrus aurantifolia, Rutaceae), see Tab. 3.19 for composition(G: Limette, F: citron vert, S: lima, limon)

The flavour of limes is used in 3 different forms:

a) as juice to impart a very special acidic juicy floral character to alcoholicbeverages and soft drinks.

b) as cold pressed peel oil to increase freshness and stability in lemon-limesoft drinks.

c) as distilled lime oil, mainly used in soft drinks of the cola or lime type.

CIC: The lemon like cold pressed lime oil is characterized by a relatively high citralcontent, balanced with beta-pinene, gamma-terpinene and neryl acetate. The distilledoil is a mixture of acid catalyzed breakdown products of terpenes: 1,4-cineole, 1,8-cineole and alpha-terpineol are the backbones of this oil, rounded off with gamma-terpinene, other terpene hydrocarbons and alcohols.

(4) Grapefruit (Citrus paradisi, Rutaceae), see Tab. 3.17 for composition(G: Pampelmuse, F: pamplemousse, S: toronja)

The taste of grapefruit juice is acid, fruity, bitter sweet. The peel oil has a character-istic terpeny, woody, exotic fruity character.

CIC: The bitter taste originates from naringin. Nootkatone imparts the characteristicfresh woody odour. Acetaldehyde and ethyl butyrate improve the juicy note and 1-p-menthane-8-thiol is responsible for the typical exotic grapefruit character.

(5) Mandarin, Tangerine (Citrus reticulata, Rutaceae), see Tab. 3.20 for composition(G: Mandarine, F: mandarin, S: naranja-cravo)

The taste of freshly consumed mandarins is very juicy, sweet fresh with the character-istic heavy aromatic aldehydic flavour. The processed juice is not stable. Its flavourturns into an unpleasant phenolic “skunky” off flavour. The peel oil keeps its originalaromatic sweet odour and is often used to modify orange flavourings into sweeter,more aromatic products.

CIC: The basis of the heavy aromatic flavour is methyl-N-methyl anthranilate incombination with gamma-terpinene. The orange citrus note results from the presenceof octanal, decanal and alpha-sinensal.

Coconut, Macapuno (Cocos nucifera)(G: Kokosnuss, F: noix de coco)

Fresh coconut milk has a sweet juicy, fruity, slightly creamy, fatty flavour. Roastedcoconut meat develops a nice creamy, nutty characteristic odour and taste.

CIC: The typical creamy-fatty note is produced by delta-octalactone and delta-deca-lactone, balanced with free fatty acids C8-C12 and 2-nonanone. The flavouring indus-try mainly uses gamma-nonalactone (the so called “coconut lactone”) to impart thetypical coconut flavour. The roasted coconut meat contains in addition pyrazines.


Grape, Raisin (Vitis spez., Vitaceae)(G: Traube, F: raisin, S: uve)

Grapes are the most important fruits produced, but 90 % are processed to wine. Awide range of species and hybrids exist, optimized for good wine production. Theconsumed fruits can be separated into two broad groups:

– the white Muscat type with a very sweet floral fruity character– the blue concord type with a succulent fruity aromatic aroma, more or less

dominated by a typical catty aromatic topnote.

CIC: The basic Muscat note is produced from linalool, balanced with further terpenealcohols, geraniol and linalool oxides. The catty odour of the concord grape is basedon methyl anthranilate, combined with ethyl-3-mercapto propionate, benzaldehydeadds the touch of a seedy character.

Hazelnut, Filbert (Corylus avellana)(G: Haselnuss, F: noisette)

The taste of fresh filberts is somewhat fatty, metallic nutty and is strongly improvedby the roasting to become nutty roasted.

CIC: The flavour of freshly roasted filberts, is a balanced composition of alkylpyrazines and aldehydes, derived from the Maillard reaction in combination with 4-methyl-5-hepten-2-one.

Peach (Prunus persica, Rosaceae)(G: Pfirsich, F: peche, S: melocoton, I: pesca)

The taste of ripe peaches is dominated by the sweet succulent juice with its veryaromatic fruity and fresh aroma. The heavy fruity, fatty, typical peachy note, alsofound in plums, nectarines, apricots is called “lactony”, and it is derived from gamma-lactones.

CIC: The typical “lactony” note is produced by 4-decanolide. The flavour industrysince years uses mainly the 4-undecanolide, the so called “peach lactone”. The lac-tone has to be balanced with fruity esters like 3-methyl butyl acetate, the floral-fruitynote of linalool and some green notes like (E)-2-hexenal.

Pear (Pyrus communis, Rosaceae)(G: Birne, F: poire, S: pera, I: pera)

The sweet juicy, fruity taste of pears is accompanied by a typical sweet, fruity, fattypear note.

CIC: The typical fruity, fatty pear note originates from ethyl-(E,Z)-2,4-decadienoatebalanced with ethyl-(E)-2-octenoate and ethyl-(Z)-4-decenoate. Farnesene adds afresh floral terpeny topnote and esters, mainly hexyl acetate, contribute to the fruity,estery character.


Pineapple (Ananas comosus, Bromeliaceae)(G: Ananas, F: ananas)

Ripe, fresh pineapple has a sweet, acid, slightly biting taste with a fragrant, sweet,fruity, fresh aroma combined with a fruity caramel like aftertaste.

CIC: Methyl hexanoate represents the fresh, fruity character, ethyl-3-(methyl-thio)propionate imparts an overripe impression, 1-(E,Z)-3,5-undecatrien adds a freshgreen, biting topnote and 2,5-dimethyl-4-hydroxy-furan-3(2H)-one is responsible forthe ripe, sugary, fruity, caramelic lasting aftertaste. Allyl hexanoate is often used incompounded pineapple flavourings.

Raspberry (Rubus idaeus, Rosaceae)(G: Himbeere, F: framboise, S: farmbuesa, I: lampone)

Common cultivated raspberries often have nice shape and colour, but their taste is justwatery and acidic. Fragrant raspberries develop a delicious fresh, fruity, green, floral,violet like perfume with some seedy, woody background. Ripe raspberries are sweetand very juicy.

CIC: The main flavouring components are alpha-and beta-ionone with their floral,violet and typical perfumy, raspberry, woody character. 1-(4-hydroxyphenyl)butan-2-one imparts the fruity, sweet raspberry body. (Z)-3-hexenal is responsible for thefresh, green topnote and 2,5-dimethyl-4 hydroxy-furan-3(2H)-one adds the overripe,almost cooked fruit jammy body.

Strawberry (Fragaria spez., Rosaceae)(G: Erdbeere, F: fraise, S: fresa, I: fragole)

Strawberry varieties are subject to a wide variety of breeding programs due to theircommercial importance. Strawberries are world-wide appreciated by their character-istic flavour, but industrial processing and international transports call for colourful,firm, large, stable strawberries. In most cases the delicious flavour suffered. Thustoday many consumers know only the dull, acid, green, forced ripened but wellshaped, colourful strawberries from the supermarket. They are not aware of thefragrant, sweet, fruity, aromatic, juicy flavour of wild or garden ripened strawberries.Strawberries, like many other fruits, show a very active flavour development: dailychanges of flavour concentrations as well as very fast development of new compo-nents after cell disruption have been observed.

CIC: The basic flavour complex of strawberries is built of 2,5-dimethyl-4-hydroxy-furan-3(2H)-one and 2,5-dimethyl-4-methoxy-furan-3(2H)-one. Both impart the ripe,fruity, caramel, cooked character together with ethyl hexanoate, the fresh fruity,estery note. (E)-2-hexenal and (E)-2-hexenyl acetate are responsible for the fresh,green impression. 2-Methyl butanoic acid leads to a refreshing fruity acidity, S-methyl butanthioate and 4-hydroxy decanoic acid lactone improve the overripe char-acter; linalool characterizes the fruity, floral note of the variety Senga Sengana andmethyl anthranilate turns a garden strawberry into a wild strawberry. The flavouringindustry uses in addition to these strawberry components other synthetic materials

Sensorially Interesting Fruit Flavours 419

like maltol, ethylmaltol, and ethyl-2-methyl phenyl-glycidate, the so-called “straw-berry aldehyde”.

4.2.3 Sensorially Interesting Fruit Flavours

In the world of fruits many other sensorially interesting fruits exist. Most of them areknown only locally, and they are unknown to the consumers in the large markets.Especially many tropical fruits have never been exploited for their commercial valueand they run the risk to disappear from the biosphere. Some have found an interest inhome made products:

Blueberry, Billberry (Vaccinium myrtillus), Cranberry (Vaccinium macrocarpon) andGooseberry (Ribes grossularia) with their fresh, sour, green, astringent flavour arenow produced in larger quantities.

Naranjilla, Lulo (Solanum quitoense) with its fantastic sour taste with a touch ofapricot, an exotic note of ethyl benzoate. Its juice has a nice green colour when freshlypressed. Unfortunately it has a very delicate skin when ripe and thus it cannot betransported over long distances. Moreover it does not properly ripen after harvesting.

Jabuticaba (Myrciaria cauliflora) is a cherry-like fruit from Brazil with a gelatinousflesh and a very sweet, sour taste and a flavour in the direction of concord grape,black currant, raspberry and vanilla.

Pomegranate, grenadine (Punica granatum) contains in its kernels a very refreshingjuice with a high tannin content (which may cause strong discolouring on cloth). Thetaste is sour/sweet with a fruity, berry-like aroma, reminiscent of raspberry and redcurrant with a touch of an earthy, green bell pepper note. The taste of “grenadinesyrup” in Europe is a mixture of sweet raspberry with vanillin, quite different fromthe original fruit and resembles a little bit the “American Cream”.

Sapotilla, Chico (Achras sapota) is the fruit of the chicle tree, the source of the naturalchewing gum base. The fruit has a very sweet taste with a pear-like, soft structure.The flavour is reminiscent of a mixture of pear with hazelnut.

Blackberry, Brambles (Rubus fructicosus, Rosaceae)(G: Brombeere, F: mure, S: mora, I: mora)

Ripe, wild blackberries have a strong, sweet, heavy fruity, floral musky and sugaryflavour.

CIC: The key components are 2,5-dimethyl-4-methoxy-furan-3(2H)-one with its sug-ary sweet fruity aroma combined with aromatic fruity p-cymen-8-ol. The floral noteis supported by dihydroactinidiolide, 14-cyclotetradecanolide and 16-cyclo-hexadecanolide.

Cape Gooseberry (Physalis peruviana, Solanaceae)(G: Kapstachelbeere, F: Andenbeere, S: uvilla, membrillo)

The taste of this decorative fruit is very acid, refreshing, fruity and juicy. The flavouris aldehydic fatty, especially on the skin: fine droplets of a strongly flavoured oildevelop when ripe.


CIC: The fatty aldehydes octanal, nonanal, decanal together with the correspondingfatty acids and their ethyl esters are responsible for the characteristic fatty aldehydicflavour of the skin. (E)-2-hexenal, hexanal and (E)-2-pentenal contribute to the re-freshing character, supported by the high acidity of the juice. Methyl-2-methyl bu-tanoate, methyl-3-methyl butanoate and methyl hexanoate impart a fresh, fruity note,rounded off with traces of methyl benzoate, methyl salicylate and the sweet floralnote of beta-ionone and damascenone.

Custard Apple, Cherimoya (Annona cherimola, Annonaceae)(G: Cherimoya, S: Chirimorrinon)

This delicious fruit started to become available in the northern hemisphere during thepast 20 years. Its sweet, creamy, fruity taste is reminiscent of fresh cream withstrawberries, pineapple and a floral aromatic exotic background in the direction ofylang-ylang, a flower of the same annona family.

CIC: Fruity esters like 3-methylbutyl acetate, 3-methylbutyl-3-methyl butanoate,ethyl-3-methyl butanoate represent the fruity estery character. Linalool and its deriv-atives, the linalool oxides add a fruity floral note; 2,5-dimethyl-4-methoxy-furan-3(2H)-one, gamma-nonalactone together with the high sugar and low acid content areresponsible for the sweet, creamy taste and methyl-2-hexenoate in combination withbenzyl esters (acetate, 2-methyl propanoate, butyrate) impart the typical exotic Cher-imoya character.

Soursop (Annona muricata, Annonaceae)(G: Stachelannone, Sauersack, F: corossol, S: Guanabana)

This tropical fruit, rich in juice and seeds, a native of South America, has a veryrefreshing sour sweet, juicy taste with a specific green, fruity powerful exotic freshflavour reminiscent of pineapple. The background is spicy floral perfumistic in thedirection of ylang-ylang with cinnamon.

CIC: The typical basic exotic green note is produced by methyl-2-hexenoate andmethyl hexanoate. Cinnamyl alcohol and methyl cinnamate add the spicy cinnamonnote and linalool together with benzyl acetate form the basic floral, perfumisticbackground.

Sweetsop, Sugar Apple (Annona squamosa, Annonaceae)(G:Schuppenannone, F:pomme canelle, S:Anon, P:Fruta do conde)

This tropical fruit from Brazil is difficult to be eaten due to its granular surface. Butthe creamy pulp has a delicious, very sweet, strawberry, cream, slightly sweet-floral,weak ylang-ylang flavour. The fruity estery character is considerably weaker than inthe cherimoyas.

CIC: 2,5-Dimethyl-4-methoxy-furan-3(2H)-one and gamma-nonalactone form thesweet, creamy heart of the profile, surrounded with esters like ethyl caproate, ethylbutyrate, ethyl-2-methyl butyrate and floral, fruity notes like linalool and benzylacetate.


Cloudberry (Rubus chaemamorus, Rosaceae)(G: Multebeere)

Cloudberries have the same shape as raspberries, but a different, yellow-orangecolour. The taste is completely different: no fresh, fruity and violet character, butsour, fruity, juicy, aromatic spicy in the direction of cinnamon, clove.

CIC: p-Cymen-8-ol, 2-heptanol and myrthenol impart the basic blackberry note,modified by floral fruity notes of linalool, 2-phenyl ethanol, geraniol and character-ized by the aromatic, medicinal note of methyl benzoate embedded in the spicycinnamyl alcohol, methyl cinnamate and 4-vinyl phenol.

Durian (Durio zibethinus, Bombacaceae)(G: Stinkfrucht)

Nicknames like “stinkfruit”, “the king of fruits” and the separation of people into“durian eaters” and “durian haters” clearly shows the polar character of this specialfruit. Descriptions like: old cheese, rotten onion, rotten egg, turpentine, creamy,buttery, custard, vanilla cream, brown sherry, strawberry cream, hazelnut cream sup-port its mysterious taste. It is quite obvious that ripe durians produce such a bestialstench that its transport in public transport systems is specially regulated. Peopleunfamiliar with durians avoid the contact with them. Whoever dares to eat a spoon ofthe yellow, soft, creamy mass surrounding the large seeds, is surprised by its mild,delicious, sweet, creamy taste reminiscent of a combination of strawberries with fullfat cream, vanilla cream, a few hazelnuts and a slight topping of fresh, ripe onions.

CIC: The main components, responsible for the repulsive odour are 1-propanethiol,ethanthiol and methanethiol, and the corresponding sulfides. Ethyl butyrate and ethyl-2-methyl butyrate impart the fruity, fresh strawberry character. Components likevanillin, 2,5-dimethyl-4-hydroxy-furan-3(2H)-one, 3-methyl-cyclopent-2-en-2-ol-1-one, gamma-decalactone (all not yet identified in Durian) may support the creamynutty character.

Guava (Psidium guajava, Myrtaceae)(G: Guave, F: goyabe, S: guayaba)(G: Guave, F: goyabe, S: guayaba)

Ripe guavas develop such a powerful odour that a whole room can be perfumed bytheir smell. The taste varies according to its degree of ripeness: from sour, green,harsh, over fresh, fruity pineapple and pear like to spicy, cinnamon, creamy, quince-like with some astringent aspects.

CIC: The powerful odour is dominated by 2-isobutyl thiazole and 3-pentanethiol. Thegreen notes are lipid degradation products like (E)-2-hexenal, hexanal and higherunsaturated aldehydes, the pineapple-pear like fruity notes are derived from methylhexanoate, ethyl-2-hexenoate and hexyl acetate. The spicy cinnamon notes are repre-sented by 3-phenyl propyl acetate, cinnamyl acetate, methyl cinnamate, ethyl cinna-mate and cinnamaldehyde. Gamma-decalactone and 2,5-dimethyl-4-hydroxy-furan-3(2H)-one and 3-hydroxy-2-butanone add the sweet, creamy body. Beta-farnesene,citronellol, 2-phenylethanol, beta-ionone add the sweet, floral, quincelike part andmethyl benzoate and ethyl benzoate impart a characteristic medicinal, exotic topnote.


Lychee, (Litchi chinensis, Nephelium lappaceum, Sapindaceae)(G: Litschi, S: mamoncillo chino)

The fruits has the size of a small plum and a skin like a red speckled egg shell. Itcontains a very succulent, juicy, watery pulp with a sweet, perfumistic, rosy, fruitytaste.

CIC: 2-Phenylethanol, citronellol, geraniol and linalool are responsible for the floralrosy background; roseoxide adds an exotic floral rosy topnote. 3-Methyl butyl acetate,2-methyl-2-buten-1-ol, 1-ethoxy-3-methylbut-2-en and menthol add the fresh, fruitycharacter.

Kiwi, Chinese Gooseberry (Actinida chinensis, Actinidaceae)(G, F, S, I: Kiwi)

The taste of fresh kiwi fruit is refreshing with a very clean acid juice. Its aroma isgreen like a fresh cut apple with fresh strawberries and gooseberries. Overripe, staleor cooked kiwis have lost their refreshing green, acid character and develop a dull,fatty, estery fruity, non characteristic flavour.

CIC: Vitamin C (300 mg/100 g fruit), citric acid and malic acid are responsible for theclean acidic taste of the fresh fruit. A high enzyme activity of a lipoxygenase pro-duces high amounts of (E)-2-hexenal, hexanal and (E)-2-hexenol, all fruity greennotes, characteristic of green apples. The cut surfaces develop at prolonged standing2-heptenal, 2,4-nonadienal and 1-octen-3-one, responsible for stale, fatty odour. Me-thyl butyrate and ethyl butyrate impart the ripe, fruity, estery, fresh, juicy impression.

Mango (Mangifera indica, Anacardiaceae)(G: Mango, F: mangue)

To describe the flavour of a mango is a rather difficult task. Since the mango tree isone of the oldest cultivated trees, many different cultivars with different tastes andflavours exist. The taste may vary from very sweet, pulpy like ripe canned peaches tovery sour. The consistency of the pulp varies from soft, creamy, buttery to veryfibrous. The flavour in general is characteristic sweet, fruity, creamy, floral with acanned peach character, topped with a more or less accentual terpeny, green, resinousnote. This terpeny note is a characteristic difference of cultivars: Indian Alphonsomangoes have a weak fresh sweet citrus green terpeny character with a full, sweet,peachy overall taste. The Carabao mangoes of the Philippines are characterized bytheir fresh, green, herbaceous, parsley-like terpene topnote, combined with a full,sweet exotic fruity apricot like body. Mangoes from Sri Lanka and Malaysia arecharacterized by their green, resinous, pine needle-like terpeny topnote and a morefibrous pulp. Due to the well accepted fantastic taste of fresh mangoes and theirnutritious value as a fresh food, the cultivars are crossed and spread all over thetropical and subtropical zones.

CIC: Three basic cultivar types can be distinguished chemically:

– the ocimen type: (Z)-ocimen in combination with beta-caryophyllene impartthe sweet, citrus, woody terpene notes like the Alphonso cultivar.


– the carene-type: delta-3-carene with beta-caryophyllene impart the green,woody,herbaceous, parsley-like terpene notes like in the Carabao type.

– the terpinolene type: alpha-terpinolene and beta-selinene impart the greenresinous pineneedle-like terpene notes like in the Malaysian mangoes.

These terpene notes are supported by (Z)-3-hexenol, (E)-2-hexenal, (E)-2-hexenolwith their fresh, green character. Gamma- and delta-lactones (4-decanolide, 5-decan-olide, 4-dodecanolide, 5-dodecanolide-(Z)-7-decen-5-olide) impart the sweet,creamy, buttery, peach and apricot character. 2,5-Dimethyl-4-hydroxy-furan-3(2H)-one and 2,5-dimethyl-4-methoxy-furan-3(2H)-one are responsible for the sweetcreamy fruity body. A bouquet of esters imparts the overall fruity character (mainlyesters of ethyl-, (Z)-3-hexenyl and butyl alcohol with acetic-, butanoic-, 2-butenoic,3-hydroxybutanoic- and hexanoic acid).

Alcohols like 3-methyl-2-buten-1-ol, citronellol, nerol, hotrienol, linalool and 2-phe-nylethanol impart a fresh floral topnote to the whole mango flavour. Artificial mangoflavourings may contain diphenyl oxide or styrallyl acetate.

Melon (Cucumis melo, Cucurbitaceae), Muskmelon, Sugarmelon Watermelon (Citrullus lanatus, Cucurbitaceae)

(G: Melone, F: melon, S: melon)

The taste of the muskmelon is very sweet creamy with a strong, sweet, floral fruity-sulphurous and typical melon-like, fatty, green aroma. The taste of watermelon isvery watery, juicy, sweet with a weak green, fatty, cucumber-like aroma.

CIC: In both melon types the lipid degradation products (Z)-6-nonenol, (Z,Z)-3,6-nonadienol and the corresponding aldehydes are responsible for the typical green,fatty, cucumber melon aspect. Ethyl propionate imparts an overripe character tomuskmelon flavour, supported by the sweet, caramelic aspect of 2-methyl-5-ethyl-4-hydroxy-furan-3(2H)-one and the fruity-sulphurous aroma of S-methyl thioacetateand methyl thiobutyrate.

Papaya, Paw Paw (Carica papaya, Caricaceae)(G: Papaya, F: papaye)

Papayas are used in three different ways:

– unripe, green fruits, as well as the leafs and the stem produce a papain richlatex on scratching. Papain, a proteolytic enzyme, is used in pharmaceuticals,tanning and as meat tenderizer.

– unripe, cooked as vegetable like cucumbers, pumpkins– small, ripe fruits for fresh consumption.

The small, ripe papayas develop a strong sweet, fruity, floral, spicy aroma. Theoverripe fruit cannot be stored and develops an unpleasant butyric, sweaty, rottenodour. The numerous seeds have a strong unpleasant radish smell and a bitter burningtaste. They are not consumed.

CIC: Linalool is responsible for the basic fruity, floral topnote. Methyl-(methylthio)-acetate and butyric acid impart the butyric, rotten character and benzyl isocyanate isthe key component for the radish smell of the seeds.


Passion Fruit (Passiflora edulis, Passifloraceae)(G: Passionsfrucht, F: fruit de passion, S: maracuja)

From over 400 species of passion fruit, two became commercially important crops:the purple passion fruit, Passiflora edulis, var. purpurea and the yellow passion fruitor maracuja, Passiflora edulis, var. flavicarpa. Both are well recognized by theirdelicious, acid, gelatinous, juicy pulp with its characteristic, exotic, sharp, green,fruity, sulphurous and floral, fruity note, whereas the yellow variety is fresher,greener with a stronger sulfury note.

CIC: Green, fruity, fatty esters like (Z)-3-hexenyl butyrate, (Z)-3-hexenyl hexanoate,2-ethyl hexenoate, 2-ethyl-octenoate form the basic fruity body. Nerol oxide andedulan add an ethereal, fresh, green, sharp, floral topnote. The floral note (mainly inthe purple variety) is represented by linalool with a complex of ionone derivatives,mainly beta-ionone, dihydro-beta-ionone, theaspirone, damascenone. The key com-ponents for the green, exotic, sulfury topnote of the yellow variety are 2-methyl-4-propyl-1,3-oxathiane and 3-methylthio-1-hexanol.

Plum (Prunus domestica, Rosaceae)(G: Pflaume, F: prune, S: circuela, I: prugna)

Although there are many different cultivars of plums, we can describe their flavour ingeneral as very sweet to green, acid with a pronounced heavy, sweet, floral, “lac-tony”, spicy, fruity aroma.

CIC: The green note is represented by (Z)-3-hexenol, (E)-2-hexenol, (E)-2-hexenal.4-Decanolide contributes to the heavy, “lactony” character. The heavy floral note isthe result of a balanced mixture of linalool, 2-phenylethanol, benzyl acetate. Thespicy background, mainly from cooked plums, results from cinnamaldehyde, eugenol,methyl cinnamate with some stone notes of benzaldehyde. The fruity, fatty body isimparted by (Z)-3-hexenyl-2-methyl butyrate and ethyl nonanoate.

Prickly Pear (Opuntia ficus indica, Cactaceae)(G: Kaktusfeige, F: figue d inde, S: chumbo, tuna)

The flavour of a prickly pear is reminiscent of a combination of an unripe, granularpear with a floral melon.

CIC: (Z)-3-hexenol and (E)-2-hexenal contribute to the unripe, green character; hep-tyl acetate and ethyl 2,4-decadienoate impart the fruity pear note and 2,6-nonadien-1-ol adds the melon-like topnote.

Quince (Cydonia oblonga, Rosaceae) (G: Quitte, F: coing, S: membrillo, I: cotogna)

Fresh, raw quinces cannot be consumed as such due to their very hard, tough texture.But a tree full of ripe quinces produces a powerful, lovely floral, fruity perfume,which is destroyed during cooking.

CIC: The floral fruity perfume is the result of a balanced mixture of farnesene,linalool, ethyl-2-methyl-2-butenoate, ethyl (E)-2-(Z)-4-decadienoate, derivativesaround beta-ionone (theaspirone, theaspirane (E,E)-6,8-megastigmadien-4-one) and

Processed Flavourings 425

the quince specific components marmeloxide, quince oxepane: 4-methyl-2-(3-methyl-1,(E)-3-butadienyl) oxepane.

Starfruit (Averrhoa carambola, Oxalidaceae)(G: Karambole, F: carambole)

Cut starfruits are very decorative but their taste and flavour is disappointing: a juicyharsh, sour, earthy, medicinal, fruity aroma.

CIC: The basic acid taste results from high levels of oxalic and succinic acid. (Z)-3-hexenol and (E)-2-hexenal contribute to the unripe, green aspect and ethyl benzoatewith methyl-2-hydroxybenzoate are the typical medicinal notes. Quinoline and ethylnicotinate add the earthy background.

4.3 Other Blended Flavourings

4.3.1 Processed Flavourings, see also chap. 3.2.3

Processed flavourings play an important role in the flavour industry, as they are anessential part of human food consumption: all heated, cooked, baked, roasted fooddevelop their typical flavour via processing through the Maillard reaction, a reactionpath as complex as biochemical pathways. Therefore the flavour industry uses manybuilding blocs of processed flavourings of model systems to create cooked, baked orroasted flavourings. Many of the reaction products of roasted flavourings have a highflavour value, but a short shelf life. Subsequently processed model flavourings areused in their basic form to act as precursors.

Coffee (Coffea arabica, C. canephora, Rubiaceae)(G: Kaffee, F: cafe)

Coffee beans develop their characteristic flavour only after a carefully controlledroasting process and this flavour can be appreciated only through the “right” prepara-tion with hot water. The quality of the served coffee is quite different from one placeto the next: mild or strongly roasted coffee, prepared by cooking the coffee powder inwater or extracted through a filter or in an espresso machine, diluted “brown water”or highly concentrated “Turkish” coffee: the taste, flavour and the preferences varyfrom cup to cup. The taste may be sweet (depending on the quantity of addedsweetener), bitter (depending on the degree of the roasting process) and sour (depend-ing on the preparation method). In the flavour we can distinguish nice, nutty, hazel-nut, roasted and caramel or burnt sugar notes. Strongly roasted coffee is characterizedby roasted, burnt, tarry notes. In cold coffee we may observe woody, earthy and evenchemical, medicinal notes.

CIC: The coffee flavour is the result of a very complex Maillard reaction betweenproteins and carbohydrates (amino acids, reducing sugars), combined with reactionproducts of lipids, polyphenols and polyamines. Today over 600 components havebeen identified, contributing to the coffee flavour impression.

Important key components in coffee are:


Sulphur compounds: furfuryl mercaptane with its very strong roasted coffee, sulphur-ous burnt character. This unstable component varies its flavour profile with theconcentration. Methanethiol has a strong rotten, disgusting sulphurous odour, but atlow concentrations it enhances an interesting, freshly brewed character to the coffeeflavour.

Alpha diketones: 3-methyl-2-hydroxy-2-cyclo-penten-1-one: a burnt sugar, roasted,lingering aroma.

Phenols: guaiacol: smoky burnt, tarry, phenolic or medicinal character.

4-Ethyl guaiacol: smoky, burnt, phenolic, spicy, clove, medicinal.

Furans: furfural with its caramel, burnt, ethereal, almond character, is the mostprominent sugar degradation product. 2-Methyl-5-ethyl-4-hydroxy-dihydro-furan-3(2H)-one has a strong, sweet, caramel, bread note.

Pyrrol: 2-acetyl pyrrol contributes a caramel, burnt, slightly chemical note to theflavour.

Thiazoles: 2-acetyl thiazole imparts a roasted, crusty (bread crust, meat crust) note.Trimethyl thiazole has a nutty, green, cocoa note.

Pyridines: 2-acetyl pyridine has a roasted, nutty, earthy character.

Pyrazines: 5-methyl-6,7-dihydro-(5H)-cyclopenta-(6)-pyrazine imparts a roasted,nutty, coffee character.

Cocoa, Chocolate (Theobroma cacao, Sterculiaceae)(G: Kakao, F: cacao)

As with coffee, cocoa gets its characteristic flavour only after the “right” processing:the fermentation of the fresh fruit and the drying and roasting of the seeds. During thisroasting process precursor molecules (aromatic acids, lipids, proteins, polysaccha-rides) react in a complex Maillard reaction to develop the typical cocoa flavour: thebitter astringent, dry harsh taste, combined with a warm roasted, nutty, floral, slightlyhoney like aroma. The invention of chocolate brought a high tribute to cocoa: aharmonious combination of roasted cocoa powder, cocoa fat, heated milk powder,sugar and vanilla, skilfully processed to eliminate undesirable harsh, acid, greenflavour notes, liquefied with lecithin and homogenized to a very fine, melting massresults in a delicious sweet, roasted, nutty, creamy, caramel, floral and honey likeflavour with a harmonious bitter, sweet taste, melting on the tongue: the well appre-ciated chocolate.

CIC: The combination of theobromine, diketo piperazines and tannin is responsiblefor the balanced bitter, astringent taste. Harsh, volatile acids, like acetic acids, areeliminated during the conching process, as well as some green alkyl pyrazines.Strecker degradation aldehydes from leucine, valine, phenyl alanine (2-methyl-pro-panal, 3-methyl-butanal, phenyl acetaldehyde) and their condensation products (4-methyl-2-phenyl-2-pentenal, 5-methyl-2-phenyl-2-hexenal) form the body of thegreen, floral, honey like cocoa flavour, supported by linalool and methyl phenylacetate. The roasted character is imparted by a wide range of heterocyclic nitrogen-

Processed Flavourings 427

and sulphur components (pyridines, pyrazines, thiazoles, oxazoles). Worth mention-ing are:

– 4-methyl-5-vinyl thiazole: nutty, roasted, cocoa– 2,4,5-trimethyl oxazole: roasted, nutty, cocoa, sweet, green.– 3-ethyl-2,5-dimethyl pyrazine: green, nutty, roasted.– Vanillin and maltol (3-hydroxy-2-methyl-4-pyrone) are responsible keys for

the sweet, creamy flavour of chocolate.

Tea (Camellila sinensis, Theaceae)(G: Tee, F: the)

We roughly can distinguish 3 different types of tea:

– non fermented green tea– partially fermented Oolong tea– fermented black tea (Darjeeling).

The teas are further heat treated (steamed, roasted). These treatments explain the verycomplex nature of its flavour: we can detect astringent, bitter taste, green, fruity orfatty fresh notes, the full, sweet, floral, dry, woody, typical tea flavour, some roasted,smoky topnotes.

CIC: polyphenols are the precursors for the astringent tannic acids. Lipids are theprecursors of the green, fatty notes of green tea: (E)-2-hexenal and (Z)-3-hexenolimpart the fresh, green, fruity, grassy topnote. 2-Nonenal, 2,6-nonadienal and 2,4,6-decatrienal add the fatty, cucumber character. Carotenes are the precursors of themain floral, sweet and fruity components. Among them linalool, theaspirone, damas-cone, damascenone and ionones are the most important ones, rounded off with thewoody note of keto isophorone, and methyl jasmonate, which adds a powerful, floral,sweet odour. Alkyl pyrazines and phenols contribute to the roasted, smoky characterof black tea supported by the sweaty odour of (Z)-3-hexenoic acid.

Meat

Meat is an important part of the human diet not only as a protein source, but also, aspart of the pleasures of eating due to its wide range of unique tastes, flavours, textureand its variety of preparing it.

The basic taste of meat is a balanced combination of salty, slightly sour and sweetimpressions with metallic, typical “meaty” tastes represented by mineral salts, aminoacids, oligopeptides and the “umami”-taste of the ribonucleotides (disodium-5-inosi-nate, disodium-5-guanylate) and MSG (monosodiumglutamate). The flavour can bedifferentiated by:

– the source of the meat (species, part of the animal)– the processing (raw, cooked, roasted, fermented, cured)– the additives (spices, vegetables, fruits) used for its preparation.

All ingredients in meat (proteins, lipids, carbohydrates) react during the normal meatpreparation in a very complex chemical reaction to produce the final, highly appreci-ated flavour. It goes without saying, that each cook finds a new balance of this


chemical reaction. An extensive research on meat flavour development in the past 40years revealed over 1000 individual components contributing more or less to theoverall flavour, as well as their possible formation paths. We can differentiate thefollowing basic classes of flavours and their corresponding flavouring components:

– a general, basic, typical but non characteristic “cooked” meat character rep-resented by 2-methyl-3-furanthiol, a reaction product of 5-inosine mono-phosphate and cysteine.

– fat-derived, species characteristic, carbonyl components like (E,Z)-2,4-deca-dienal in chicken fat flavour; 4-methyl octanoic acid in mutton fat flavour;(E,Z)-2,4-heptadienal and (E,Z,Z)-2,4,7-decatrienal in fish oil.

– roasted notes from Maillard reactions like alkyl pyrazines, 2-acetyl-3-methylpyrazine or 2,3,5-trimethyl-6,7-dihydro-5(H)-cyclopenta pyrazine contributeroasted, grilled, burnt, nutty impressions.

– smoked notes of bacon and ham, represented by guajacol with smoked, tarry,medicinal, burnt, phenolic character.

– animal notes in pork from indole and skatole with their fecal, animalic,phenolic impressions.

– ammoniacal, aged, staling fish aroma from trimethyl amine– green, fresh notes of algae, represented by (E,Z)-1,3,5-undecatrien with an

additional galbanum aspect.– cooked, boiled shrimp note characterized by N,N-dimethyl-2-phenyl ethyl

amine.

Meat flavourings are often combinations of the above mentioned chemical classeswith reaction products of:

– cysteine, vitamin B1, ribose– proteolyzed meat with lipolized and oxidized lipids– hydrolyzed vegetable proteins or yeast autolysates– nucleotide mixtures.

Savoury Flavours (see also chapter 5.4)

In order to improve creation efficiency, flavourists use a “building block concept” tocreate savoury flavours, a combination of base, middle and top notes:

The Base Notes impart the basic taste characteristic of savoury flavours like salty,sweet, acidic, umami. A simple combination of sodium chloride, sugar, citric acid,monosodium glutamate and nucleotides may do this job. More sophisticated productsare based on the protein degradation products of natural proteins. Historically, acid-degraded plant proteins (HVP) neutralized with sodium hydroxide were a perfectbase: they contained the MSG, NaCl and nucleotides in a good balance. Recent resultsshowed the presence of unwanted monochloropropanediol from the nucleophilic sub-stitution of a hydroxy group in glycerine. Therefore, HVP has been replaced by moresuitable products like autolysed yeast and fermented plant protein like soy sauce. Dueto the fermentation process and the raw materials used, the quality of these productsmay differ. The base notes are produced in large quantities, but in a limited variabil-ity.

Fermented Flavourings 429

The Middle Notes are based on reaction flavourings to impart specific complexroasted, meaty and smoky notes: roasted chicken, boiled beef, smoked ham. Theyimprove the overall taste with a general meaty background and a good mouthfeeling.Meaty middle notes are often based on the reaction of vitamin B1, cystein andreducing sugars. Fat included in the reaction modifies the product into a specificanimal direction: chicken, beef, mutton, pork.

The process to produce reaction flavourings is not just simple; therefore the variabil-ity of the middle notes is also limited for economic reasons.

The Top Notes are compositions of natural or synthetic flavouring ingredients toimpart a very specific desired aroma profile: spicy, peppery, rosemary, lime, buttery,roasted garlic notes for a clear variation. Or specific fatty notes like 2,4-decadienal, 2-nonenal to adjust the chicken flavour to a more natural impression. Top notes are veryflexible in production and can be adjusted to customer needs.

The combination of base, middle and top note allows the flavour industry veryflexible and fast answers to the demanding food industry. Many savoury applicationsrequire dry products; therefore this approach allows a “simple” powder blendingoperation of prefabricated powder bases.

4.3.2 Fermented Flavourings

Fermentation plays an important role in the development of specific, characteristicflavourings. Natural fermentation is used since thousands of years to get wine, beer orcheese. Modern biotechnological processes have been developed to produce flavour-ings and flavouring building blocks based on natural processes. There are manyimportant fermented products on the markets, produced by traditional and industrialprocesses:

– the whole range of alcoholic beverages (wine, beer, brandy, whisky, liqueur)– dairy products (cheese, yoghurt, sour cream butter)– grain and bean fermentation (bread, shoyu)– meat fermentation (fish, sausage)– vegetables (sauerkraut, kimchi).

4.3.2.1 Alcoholic Flavourings

Alcoholic beverages are the result of a yeast fermentation of sugar from varioussources. Specific treatments and storage leads to a wide variety of products with abalanced flavour: beer, wine, brandy, whisky, rum, sake etc. And when you listen toall the connoisseurs and experts, no two products are the same: plant species, soil,weather, water quality, processing and distillation technology, all influence andchange the final quality of the products. Nevertheless it is possible to distinguishsome basic flavour notes:

– fusel oil notes: alcoholic, fusel, harsh, burning, fermented, woody notes (2-methyl butanol, 3-methyl butanol).

– wine yeast or cognac oil notes: fermented, soapy, wine yeast (ethyl oc-tanoate, ethyl decanoate, octanoic acid, decanoic acid).


– rum ester notes: estery, rum, nail-varnish-solvent like (ethyl acetate, ethylpropionate).

– pungent sharp topnote: acetaldehyde, propanal, 1,1-diethoxyethane.– fruity, estery notes: fruity, banana, apple, strawberry, paint, varnish solvent-

like (2-methylbutyl acetate, 3-methylbutyl acetate, ethyl hexanoate).

Product specific flavour characters:

– williams pear fruity note: ethyl-(E,Z)-2,4-decadienoate– cherry, kirsch, bitter almond note: benzaldehyde– white wine tart taste: tartaric acid– red wine astringent taste: tannic acid– beer bitter taste: isomerized cohumulone– rum floral, dried fruit woody notes: 2-phenylethanol, damascenone– whisky smoked notes: 4-ethyl phenol, 4-ethyl-2-methoxy phenol– whisky and beer nutty, malted notes: 2-ethyl-3-methyl pyrazine, 2-ethyl-3,5-

dimethyl pyrazine– white wine sweet, fruity, muscat grape note: linalool– sherry, sake, walnut, protein hydrolyzate, sugar-like note: 3-hydroxy-4,5-

dimethyl-furan-2(5H)-one– anise brandies sweet, fennel, anise aroma: anethole.

4.3.2.2 Dairy Flavourings

The basis of all dairy products is the fresh milk from mammals, mainly from cows.The analysis of the very bland but characteristic, slightly sweet/salty flavour reveals alarge number of common flavouring materials at a subthreshold level. Although thereis no demand for a fresh milk flavouring, it is a hard challenge to a flavourist to createthe well balanced mixture of this flavour. Fresh milk is a delicate nutritional food,sensitive to deterioration by heat, light and microbiological attack. Mankind has usedthis sensitivity to produce a wide range of dairy products: starting from simple fatseparation (to get cream, butter or ghee) to fermentation products like yoghurt, yakultand fresh cheese, right through to the hundreds of different cheeses, based on bacteriaor mold fermentation. We should not forget modern industrial dairy products likeUHT treated milk, condensed milk or milk powder. All processes include the follow-ing basic reactions:

Heat: transforms ketoacids to methylketones like 2-heptanone, 2-nonanone with agreen fatty metallic blue cheese note. Hydroxyy acids form the corresponding lac-tones. The creamy, buttery, coconut-like 5-decanolide, 4-dodecanolide, 5-dodecano-lide contribute to the sweet creamy buttery flavour in cream and butter. Lactoseundergoes a caramelisation reaction to develop sweet, caramelic maltol and 4-hy-droxy-2,5-dimethyl-furan-3(2H)-one. Lactose and milk proteins react in a Maillardreaction to roasted, nutty, burnt notes such as 2,5-dimethyl pyrazine.

Lipases: release free fatty acids from milk lipids to generate a rancid, butyric, cheesy,fatty, soapy flavour. Most important are the even numbered acids C4 to C20. Incheeses from goats and sheep 4-methyl octanoic acid imparts a strong animal, goatycharacter.

Vegetable Flavourings 431

Proteases: degrade the proteins to free amino acids and oligopeptides, thus impartingsweet, sour and mainly a bitter taste to the product. Further reactions lead to thecorresponding Strecker aldehydes 2-methylbutanal and 3-methylbutanal with a pun-gent, malty, cocoa note.

Sulfurases: produce free sulphur chemicals like hydrogen sulphide, methylmercapan,S-methyl thioacetate, S-methyl thiobutyrate.

Lactic acid fermentation imparts the clean sour taste of lactic acid to yoghurt. In a sidereaction, rather high concentrations of acetaldehyde are formed, which is responsiblefor the typical yoghurt flavour.

4.3.3 Vegetable Flavourings

The taste of vegetables can clearly be distinguished from fruits: the acid/sugar ratio isreduced, the mineral content is higher, the taste is more “salty”. In most vegetables,sulphur containing substances impart a more “culinary” flavour. The fruity characteris suppressed.

For the composition of vegetable flavourings it is essential to distinguish the flavourfrom the taste part: this taste is a balanced composition of harsh, slight bitter acidswith salt, some taste enhancers (nucleotides) and sugar to impart a slight sweetness.

Asparagus (Asparagus officinalis, Liliaceae)

Asparagus develops the characteristic taste upon cooking: a vegetable-green topnotewith a strong sulphurous-sweet characteristic overall flavour.

CIC: the typical sulphurous flavour is represented by the high concentration ofdimethyl sulphide, combined with traces of 1,2-dithia-cyclo-pentene. The vegetable-green note results from 2-isopropyl-3-methoxy pyrazine, resembling raw potatoes,and 2-sec-butyl-3-methoxy pyrazine, a green bell pepper note.

Tomato (Lycopersicon esculentum, Solanaceae)

Tomatoes are eaten raw, cooked and mainly in the form of canned puree and ketchup.The taste of ripe, flavourful tomatoes (there exist many cultivars without the typicaltaste and flavour) is well balanced between sweet, sour and salty with an acid green,vegetable like, slight floral aroma.

CIC: (Z)-3-hexenal and 2-(2-methylpropyl)thiazole form the fresh, green, vegetabletopnote and a trace of damascenone is responsible for the floral background. Oncooking, the fresh note from (Z)-3-hexenal is covered by the sweet sulphurous note ofdimethyl sulfide. In canned tomatoes, the sulphurous note is supported by the spicy,clove-like aroma of 4-vinyl guaiacol and eugenol.

Potato (Solanum tuberosum, Solanaceae)

This staple food is never eaten in the raw state: the earthy taste is not quite appealingand the starch has to be transformed into an eatable form either by cooking or bybaking/frying. Boiled, cooked potatoes develop a characteristic bland balancedcreamy, sweet, sulphurous, earthy flavour. Fried potatoes are appreciated for their


roasted, crusty, fatty, earthy potato aroma, the crispy structure and the easy, “handy”consumption.

CIC: the earthy odour of fresh potatoes is represented by 2-isopropyl-3-methoxypyrazine. This earthy note is supported by the mushroom character of 1-octen-3-ol.The key component of boiled potatoes is 3-(methylthio)-propanal, balanced withdimethyl sulphide. The high reaction temperatures in baked and fried potatoes startthe Maillard reaction to form mainly heterocyclic components: 2-ethyl-3,5-dimethylpyrazine, 2-ethyl-6-vinyl pyrazine, 5-methyl-6,7-dihydro-(5H)cyclopenta-pyrazine,2-acetyl-1,4,5,6-tetrahydro-pyridine are responsible for the roasted, nutty cracker-likeflavour. The heat-induced degradation of the potato lipids and the frying oil imparts afatty, tallowy character to the french fried potatoes. (E,E)-2,4-Decadienal, 2-octenal,octanoic acid and decanoic acid are main contributors to this fatty note.

4.3.4 Vanilla Flavourings (Vanilla planifolia, Orchidaceae)(G: Vanille, F: Vanille)

The delicious flavour of cured vanilla beans is appreciated since its discovery inMexico. Its combination with cocoa and milk started the success of chocolate. Its usein soft drinks (Cola) and ice cream and in many other applications makes it one of themost important flavour types. The rich flavour shows many aspects: the basic creamy,sweet odour is surrounded by warm, woody, slight phenolic, smoked notes (thevanilla bean character). Rum notes, combined with dried fruit, slight floral notesround off the whole picture.

CIC: Vanillin, the main component in vanilla flavour is the basic key ingredient forthe creamy, sweet character. All other volatile flavouring compounds have beenidentified only in small traces. Among them 2-methoxy phenol and 2-methoxy-4-vinyl phenol are responsible for the phenolic, smoky odour. 4-Methoxy benzalde-hyde, 3,4-methylene-dioxy-benzaldehyde, methyl benzoate and methyl cinnamateimpart the warm, powdery, aromatic floral character. Vitispirane adds a fruity, floraltopnote. Natural vanilla extract blends very well with other flavourings and it hasbeen modified in different directions: ethyl vanillin is used to increase the sweet,creamy vanillin aspect. Tonka beans and coumarin add a full, dried hay, slightlycaramel-like custard aspect, supported by the butter notes of diacetyl and 4-hydroxy-decanolide.

4.3.5 Fantasy Flavourings

Flavourings are mainly derived from natural prototypes. Many food producers arelooking for fantasy flavourings. However the success in the market is rather limited.Consumers are conservative; they do not immediately accept new, unknown tastes. Infragrances, novelties and new ideas are essential for success, but flavourings arecompared always to the natural sources.

Nevertheless, there are a few successful fantasy flavourings on the market, and it isthe dream of all flavourists to create a new taste not yet known. In most casesmodifications and combinations of natural models are the extreme points of accept-ance.

Fantasy Flavourings 433

Cola

The cola flavour is an unequalled success story since the invention of the cough syrupby Dr. Pemperton: This fantasy flavour is the dream of all flavourists: to create a new,non-existing taste with a world-wide success which by now lasts over 100 years.Without detracting from the real success and quality of this flavour, we have to set themystery of the cola flavour into relation to reality. The very well balanced fresh,citrus, lime, lemon topnote with the sweet, spicy, cinnamon, creamy, vanilla heart andthe earthy, sweet sour taste can be imitated to a certain level. However, it never willbe possible to imitate the success of the beverage: over 100 years of intensivesuccessful marketing and the largest budget for world-wide advertising, combinedwith a high quality product and good world-wide service are the basis of this successstory.

CIC: The main key products for a cola flavouring are:

– a well balanced mixture of soluble distilled lime with lemon oil– a clean cinnamon extract combined with vanilla extract– a trace of cola nut extract, caffeine and caramel colour– a balance of the sugar (or sweetener) and citric/phosphoric acid equilibrium.

Tutti Frutti

Tutti Frutti is another fantasy flavour combination, non existant in nature. It is mainlyused in chewing gums. The name suggests a mixture of all fruits. In fact it is mainlya balanced mixture of isoamyl acetate with orange oil, lemon oil and vanillin.

REFERENCES

Instead of giving a detailed list of literature references, I prefer to list a few informa-tions for a flavourist’s library.

Literature on the botany of fruits:

[1] B. Kranz, Das grosse Buch der Früchte, Südwest Verlag Stuttgart 1988[2] A. Fouqué, Espèces Fruitières d’Amerique Tropicale, Institut francais de la recherche fruitières

outre mer 1975[3] S. Rehm, G. Espig, Die Kulturpflanzen der Tropen und Subtropen, Verlag Eugen Ulmer, Stuttgart

1976[4] L. Johns, V. Stevenson, Fruits for the Home and Garden, Angus & Robertson Publishers 1985[5] G. Götz, R. Silberstein, Obstsorten-Atlas, Verlag Eugen Ulmer, Stuttgart.[6] H.R. Gysin, Tropen Früchte, AT Verlag, Aarau 1984[7] F. Bianchini, F. Corbetta, M. Pistoia, Fruits of the earth, Bloomsbury Books 1988[8] S. Silva, Frutas Brasil, Empresa das Artes 1991

Literature on flavour composition of food:

[9] H. Maarse, C.A. Visscher, Volatile Compounds in Food, TNO, Zeist 1989-1994[10] H. Maarse, Volatile Compounds in Food and Beverages, Marcel Dekker Inc 1991

General literature on flavours:

[11] Flavour and Fragrance Materials, Allured Publishing Co. 1993[12] H.B. Heath, Source Book of Flavours, AVI Publishing Company Inc 1981[13] K.J. Burdach, Geschmack und Geruch, Verlag Huber, Bern 1988


[14] E. Ziegler, Die natürlichen und künstlichen Aromen, Dr. A. Hüthig Verlag, Heidelberg 1982[15] P.R. Ashurst, Food Flavouring, Blackie & Son Ltd., Glasgow 1990[16] S. Arctander, Perfume and Flavor Chemicals 2 Volumes, 1969[17] S. Arctander, Perfume and Flavor Materials of Natural Origin, 1969.[18] E. Guenther, The Essential Oils, 6 Vols., Krieger Publishing 1948[19] G.A. Burdock, Fenaroli’s Handbook of Flavor Ingredients, CRC Press 2002[20] B.M. Lawrence, Essential Oils, 6 Vols., Allured Publishing 1976-2000[21] P. Mueller, D. Lamparsky, Perfumes, Art, Science and Technology, Elsevier Applied Science 1991

Series of Monographs, Textbooks and Reference Books on Food Science by MarcelDekker Inc.:

[22] Vol.1: R. Teranishi, I. Hornstein, Flavour Research: Principles and Techniques[23] Vol.7: R. Teranishi, R.A. Flat, Flavour Research: Recent Advances.[24] Vol.9: H.T. Chan, Handbook of tropical Foods.[25] Vol.16: M. O’Mahony, Sensory Evaluation of Food: Statistical Methods and Procedures.[26] Vol.18: S.V. Ting, R.L. Rousseff, Citrus Fruits and their Products: Analysis and Technology.[27] Vol.20: Y. Kawamura, M.R. Kare, Umami: A Basic Taste.[28] Vol.30: S. Nagy, J.A. Attaway, Adulteration of Fruit Juice Beverages.[29] Vol. 32: R.H. Matthews, Legumes: Chemistry, Technology and Human Nutrition.

Series of Monographs, Textbooks and Proceedings of Conferences on the Develop-ments in Food Science by Elsevier:

[30] Vol. 115: R. Marsili Flavor, Fragrance and Odor Analysis, 2002.[31] Vol. 3: I.D. Morton, A.J. MacLeod, Food Flavours.[32] Vol. 10, J. Adda, Progress in Flavour Research, Proceedings of the 4th Weurman Flavour Research

Symposium, Dourdan, France, 1984[33] Vol. 11: J. Hollò, Fat Science, Proceedings of the 16th International Society for Fat Research

Congress, Budapest, 1983.[34] Vol. 12: G. Charalambous, The Shelf Life of Foods and Beverages, Proceedings of the 4th

International Flavour Conference, Rhodes, 1985.[35] Vol. 13: M. Fujimaki, M. Namiki, Amino-Carbonyl Reactions in Food and Biological Systems,

Proceedings of the 3rd International Symposium on the Maillard Reaction, Susuno, 1985.

Proceedings of various Conferences:

[36] R.G. Berger, S. Nitz, Topics in Flavour Research, (Freising-Weihenstephan) H. Eichhorn, D 8051,Marzling 1985

[37] D.G. Land, H.E. Nursten, Progress in Flavour Research, (2nd. Weurman Symposium, Norwich),Applied Science Publishers LDT, London 1978

[38] M. Martens, Flavour Science and Technology, (5th. Weurman Symposium, Oslo) J.Wiley & Sons1987

[39] G. Charalambous, Frontiers of Flavours, (6th. Weurman Symposium, Geneva, CH) 1990[40] R. Hopp, K. Mori, Recent Developments in Flavour and Fragrance Chemistry, (Haarmann &

Reimer International Symposium, Kioto) Verlag Chemie, Weinheim 1992[41] G. Charalambous, Flavours of Food and Beverages, (Amer.Chem.Soc. Athens, Greece) Academic

Press 1978[42] G. Charalambous, Analysis of Foods and Beverages, (Amer.Chem.Soc. Chicago) 1977[43] P. Schieberle, K.H. Engel, Frontiers in Flavour Science, Deutsche Forschungsanstalt fuer Lebens-

mittelchemie 2000[44] D. Roberts, A. Taylor, Flavour Release, American Chemical Society 2000[45] A. Spanier, F. Shahidi, et al. Food Flavors and Chemistry, Advances in the New Millennium, Royal

Society of Chemistry 2001

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